Tuesday, September 14, 2010

Changing Drivers' Behaviour

Iain Dale, the Conservative blogger and broadcaster, was very sceptical when he was forced to go on a course for speed awareness in order to save his driving licence, having been stopped doing 37mph in a 30mph zone.

He says: "I thought it would be a waste of time but it was better than losing my licence." The course, he recalls, was run by a middle-aged woman who said she never exceeded the speed limit. The attendees, who were not the boy racers Dale had expected but "virtually all over 40", were disbelieving until she explained that five years previously, her 13-year-old daughter had been hit by a car travelling at 37mph and was still receiving treatment for the injuries she sustained.

The key message Dale took away was that while half of people hit by a car going at 30mph can expect to survive, only 10% will at 40mph. "So yes, the course did have an impact on my behaviour and I became much more aware of what other people do, too," he explains. He was also struck by the fact that everyone on the course thought that motorways were the source of many accidents when, in fact, they are responsible for just 6% of fatalities even though they account for nearly a quarter of vehicle mileage.

Dale had been opposed to speed cameras and while he remains sceptical his view about them has changed: "I think they should all be relocated to urban areas where they can have a real impact in ensuring people stick to 30 mph, and that will save lives".

43 comments:

I would be in favour of increasing the national speed limit on motorways to, say, 80mph (still slower than France), balanced by having more 20mph zones near schools, a sliding scale for punishment of speeding offences (say 1 point for every 3mph you are over the limit, similarly with fines), and more enforcement of parking violations where it actually causes danger, as opposed to where councils can get the most money.

Top Gear et al. insist that there is none. A sob story from a middle-aged woman insists that there is. Neither assertion is worth anything. I don't want policies decided upon sob stories. I want to know if these cameras have made a discernible impact upon the death and injury rates of the roads around them. If they do, and they're the most efficient way to do it, then let's have some more. If not, let's not.

Ian,It's little asides like, "Half of pedestrians survive a 30mph impact whilst only 10% survive a 40mph impact." that leave me feeling a bit sceptical. The car haters and eco-freaks, for whom the end always justifies the means, should be forced to reference their claims before they are allowed to plant these memes into the national psyche.

The biggest issue I personally have with the whole speeding bandwagon is that is inappropriate speed that is the problem. The reason that there are 30 mph limits is that normally you'd expect to see pedestrians around, hence slowing traffic down to safe lives is a good idea. One problem with speed cameras is that they only detect limit breaking not inappropriate speed. The example I use is a rural motorway, clear day no traffic 70 mph is appropriate yet same road in heavy traffic & freezing fog with visibility of 100m is 30 mph too fast? If icy is forming on road surface it is.

Another problem with speed cameras is that they don't do anything else - as mentioned in the article 40% of tyres at goodyear were illegal, speed cameras don't detect that. There are whole raft of other offences that they don't detect. We need a balanced approach.

Finally poor road design can be a significant factor in accidents, spiral bends have been noted as potentially dangerous since at least 1977 (Douglas Stewart http://www.dougstewartonline.co.uk/) see A357 Cat and Fiddle as an example of a dangerous road with spiral bends

But surely we want drivers to avoid hitting pedestrians entirely, rather than crashing into them and probably not killing them. And the key factor in that is driver response, not free travelling speed prior to impact - otherwise we would have utter carnage in all speed limits above 30, which we don't.

And also bear in mind the large mileages of roads that used to have limits of 40, 50, 60 or even 70 that have been reduced to 30 in recent years - no doubt it is those where your proposed 30 mph cameras would be relocated to.

Speed is but only ONE aspect of the causation of accidents. By far and away the biggest cause is bad driving...something that cameras cant do anything about..

Neither can they detect dangerous and defective vehicles, another cause of accidents. They are powerless against drunk drivers who are a proven cause of fatal accidents. These are facts that the `speed lobby`, for that is what they are, never conveniently mention..

There is however one sure way, 24/7 , of detecting and detering errant and dangerous drivers. They used to be called Police Road Traffic Officers. But they were largely scrapped because they used to advise, caution and educate motorists and therefore didnt raise money and oh yes they cost too much....price of everything and value of nothing again!!!!

Please dont give me the `speed camera` saves lives, on its own its meaningless and appeals only to those of simple views...its 24hr coppers that saved lives and always did....

Appropriate 30mph limits should be obeyed and enforced. I would also like to see more 20mlimits near to schools etc.

The problem is many speed limits are inappropriate. Within a mile of two of where I live there are 40 limits that should be 30 (or less) outside schools. There are 30 limits in open countryside, no idea why, 50 would be fine. 70 on a sunny deserted motorway is too slow, 80 to 85 would be better and is the speed at which many cars travel anyway.

If speed limits are to be taken seriously they must be appropriate.

Having said that, speed limits have no effect on the most dangerous drivers, the drunks, the uninsured boy racers etc. I suspect that many bad accidents that lead to the installation of speed cameras are caused by this type of driver not the middle aged person exceeding the limit by 7 or 8

There is no empirical evidence that speed cameras save lives. Some of the countries most dangerous roads do not have speed cameras. i suspect you would find that stupidity is a major factor in accidents.

The number of children killed on roads is very small (it would be nice if it were smaller). Road deaths do fall disproportionately on the young - drivers that is - and on motor cyclists.

A successful speed camera would catch no one. None of the people at Mr Dales session had had an accident, they had just edged over an arbitrary limit in an arbitrary area. There is no evidence to suggest anyone anywhere was in danger from them as they passed and no evidence to suggest that if they had seen a potential danger (ie a child) that they would have not have avoided any danger/contact.

In short speed cameras are not safety cameras they are money/job creation cameras. Road safety is no being addressed by them and if 'they' were interested in road safety 'they' would implement sensible road calming measures and make sure that black spots were permanently policed by well advertised cameras. Oh and intelligently, rather than blindly, encourage/police safe driving

Children should not be hit at all by cars, whether it be at 27 or 37MPH.

PS - clever of you Mr Dale to put up a post guaranteed to generate a huge response.

Speed is a very very small part of accidents. I think Topgear said that it was a factor in 6% of them. There are far more contributing factors, many people should go back and drive a average car from the 50's and 60's (the period when current speed limits were set) and see how bad the brakes were. Cars are hugely safer than they were even 15 years ago but you never hear much said about that when road deaths decrease. I think that more people die of hospital infections than on the roads. The there workers rarely get fined or loose their licence for infecting people I am sure.

Currently VOSA and Europe want to introduce a biannual MOT (a MINIMUM road safety standard) after the first four years of a cars life. Currently the fail rate is 37% a figure which does not include cars which have been fixed just before the MOT and ones which should not have passed due to bad testers. I would put the figure to more like 50%. The means that the we will have cars running round for two years without being checked, when the government's own figures mean 37% cars fail after one year! I would think very carefully before you step out into the road even if a car is going slow.

Speeding and poor judgement cause accidents on the road, for example if it`s raining slow down, if it`s foggy slowdown and put fog lights on, all the spped cameras in the world want stop an idiot on the road. education education education sorry if i sound like a tory lol

"I think they should all be relocated to urban areas where they can have a real impact in ensuring people stick to 30 mph, and that will save lives"

One of the reasons that the whole issue has become so messy is that the debate is often more about selective enforcement of the law rather than the efficacy of the law per se.

"The key message Dale took away was that while half of people hit by a car going at 30mph can expect to survive, only 10% will at 40mph."

Indeed, but where does this logic end? Take it to its conclusion and all cars would be banned or at least limited to 0 mph!

But the argument is used to justify the increasing use of lowered limits - and 20 mph zones in particular - which are routinely ignored and indeed not enforced; if the powers that be are incapable/unwilling to enforce existing limits then what's the point in lowering them?

Of course, the rationale is not necessarily to reduce speeds to x mph but merely to reduce traffic speed BY x mph, which an actuarial analysis will say should reduce road casualties by y.

But the crudity of it all may have unintended consequences. For example, drivers increasingly drive with a view to avoiding law enforcement measures rather than to comply with the law per se - ie slow down merely for the cameras and speed humps, an approach perhaps tacitly endorsed by officialdom - so what are the wider implications of this? I doubt if the models take account of the broader perspective.

I am an ex police patrol driver and I have to challenge certain statements in Driving for Change in Behaviour by Christian Wolmar. 14/9 http://bit.ly/b7ord2

He says that the statistics show that the Association of British Drivers has it wrong about too much focus on speed. Clearly, like Ian Dale, who he quotes and the course instructor at Dale's speed awareness course, neither he nor they are experts in driving accidents or road safety. Worse the instructor is not at all altruistic in her message and in any case, being a mother of an accident victim, is no qualification either. Therein lies the problem. Too many non experts having a big say in this life and death matter. The Parliamentary Advisory Committee of Transport Safety, he quotes, is actually nothing more than an important sounding private lobby group with vested interests and without any experts either.

Of course speed is a factor in all road accidents; without speed nothing would be moving on the road at all. So when Julie Townsend of BRAKE says 'It's a contributor to a majority of crashes', I would like her to describe any accident, whether involving planes, trains, bikes or even running, where it is not a 'contributor'. So much for the experts of BRAKE then; perhaps they should just stick to victim support.

But the figures quoted by Wolmar are totally bogus too. For a start, physics would not support the notion that to exceed an arbitrary and unscientific number on a pole, 'speeding' will cause an accident any more than not to won't. Too fast causes them, is often below speed limits and thus most accidents are below the speed limits. Unfortunately most reporting officers are not specialists and do not know this. So all the 28% shows is that 28% of reporting officers ticked a box that should not be there anyway. The correct figure is zero per cent because speeding causes nothing. The millions of speeding tickets issued should each have been after a crash if it were not so.

Christian Wolmar also uses a term favoured by the officials, BRAKE and PACTS. 'Excessive speed'. Where is this in traffic law? It does not exist. It is an element of reckless driving and is nothing to do with 'speeding'. One causes accidents and the other is just coincidental to them. Why has he readily accepted a term, not even recognised in traffic law? It is used liberally by the mighty and aggressive Road Safety Industry, criminally to my mind, to confuse reckless driving with 'speeding' in order to justify a profitable policy of unnecessarily hampering and criminalising perfectly safe drivers and to ignore real accident causes whilst doing it. I refer to this effect as 'Speed Kills! kills'.

But what is the issue anyway? After 300 billion driver miles a year there is less death on the road, from all causes, than from accidents in the home. I think the answer can be found in the countless billions of pounds being consumed yearly by an insatiable Road Safety Industry; I can think of no other explanation for all this nonsense.

Re: "...run by a middle-aged woman who said she never exceeded the speed limit. "

"Show me someone who says that they have never exceeded a speed limit, and I'll show you a liar, or a menace.".

Austin Williams, Transport Research Group.

And the other concerning the obsession with policing speeding:

I actually believe in casualty reduction and trying to make the roads safer but, having looked at the accident statistics in this area, we find that if you break down the 1,900 collisions we have each year only three per cent involve cars that are exceeding the speed limit. Just 60 accidents per year involve vehicles exceeding the speed limit.

You then need to look at causes of these 60 accidents. Speed may be a factor in the background but the actual cause of the accident invariably is drink-driving or drug-driving. Drug-taking is becoming more of a problem. In 40 per cent of fatal road accidents in this area one or more of the people involved have drugs in their system.

Many accidents were caused by fatigue, although one of the most common causes of crashes was the failure of drivers to watch out for oncoming vehicles when turning right. The cause of accidents is clearly something different than exceeding the speed limit and we ought to be looking at those other factors.

Before we say 'speeding is a crime' shouldn't we ask what 'experts' set the limits and shouldn't they be scientific and rationale? After all if we are to criminalise people, take their licences away, there has to be a little bit of logic to it?

I voluntarily survey many speed limit orders and I can verify that most I examine have no reasons, science or justification attached to them at all. I can tell you that 'it's ?? for a reason' should read 'it's usually ?? for no good reason at all' and that is appalling.

I am an ex police patrol driver and I have to challenge certain statements in Driving for Change in Behaviour by Christian Wolmar.

He says that the statistics show that the Association of British Drivers has it wrong about too much focus on speed. Clearly, like Ian Dale, who he quotes and the course instructor at Dale's speed awareness course, neither he nor they are experts in driving accidents or road safety. Worse the instructor is not at all altruistic in her message and in any case, being a mother of an accident victim, is no qualification either. Therein lies the problem. Too many non experts having a big say in this life and death matter. The Parliamentary Advisory Committee of Transport Safety, he quotes, is actually nothing more than an important sounding private lobby group with vested interests and without any experts either.

Of course speed is a factor in all road accidents; without speed nothing would be moving on the road at all. So when Julie Townsend of BRAKE says 'It's a contributor to a majority of crashes', I would like her to describe any accident, whether involving planes, trains, bikes or even running, where it is not a 'contributor'. So much for the experts of BRAKE then; perhaps they should just stick to victim support.

But the figures quoted by Wolmar are totally bogus too. For a start, physics would not support the notion that to exceed an arbitrary and unscientific number on a pole, 'speeding' will cause an accident any more than not to won't. Too fast causes them, is often below speed limits and thus most accidents are below the speed limits. Unfortunately most reporting officers are not specialists and do not know this. So all the 28% shows is that 28% of reporting officers ticked a box that should not be there anyway. The correct figure is zero per cent because speeding causes nothing. The millions of speeding tickets issued should each have been after a crash if it were not so.

Christian Wolmar also uses a term favoured by the officials, BRAKE and PACTS. 'Excessive speed'. Where is this in traffic law? It does not exist. It is an element of reckless driving and is nothing to do with 'speeding'. One causes accidents and the other is just coincidental to them. Why has he readily accepted a term, not even recognised in traffic law? It is used liberally by the mighty and aggressive Road Safety Industry, criminally to my mind, to confuse reckless driving with 'speeding' in order to justify a profitable policy of unnecessarily hampering and criminalising perfectly safe drivers and to ignore real accident causes whilst doing it. I refer to this effect as 'Speed Kills! kills'.

But what is the issue anyway? After 300 billion driver miles a year there is less death on the road, from all causes, than from accidents in the home. I think the answer can be found in the countless billions of pounds being consumed yearly by an insatiable Road Safety Industry; I can think of no other explanation for all this nonsense.

It says that the statistics show that the Association of British Drivers has it wrong about too much focus on speed.

Ian's instructor is not at all altruistic in her message and in any case, being a mother of an accident victim, is no qualification either. The

Parliamentary Advisory Committee on Transport Safety, quoted, is only an important sounding private lobby group with vested interests and without any experts in it.

Of course speed is a factor in all road accidents; without speed nothing would be moving on the road at all. So when Julie Townsend of BRAKE says 'It's a contributor to a majority of crashes', I would like her to describe any accident, whether involving planes, trains, bikes or even running, where it is not a 'contributor'. So much for the experts of BRAKE then; perhaps they should just stick to victim support.

But the figures quoted by Wolmar are totally bogus too. For a start, physics would not support the notion that to exceed an arbitrary and unscientific number on a pole, 'speeding' will cause an accident any more than not to won't. Too fast causes them, is often below speed limits and thus most accidents are below the speed limits. Unfortunately most reporting officers are not specialists and do not know this. So all the 28% shows is that 28% of reporting officers ticked a box that should not be there anyway. The correct figure is zero per cent because speeding causes nothing. The millions of speeding tickets issued should each have been after a crash if it were not so.

Christian Wolmar also uses a term favoured by the officials, BRAKE and PACTS. 'Excessive speed'. Where is this in traffic law? It does not exist. It is an element of reckless driving and is nothing to do with 'speeding'. One causes accidents and the other is just coincidental to them. Why has he readily accepted a term, not even recognised in traffic law? It is used liberally by the mighty and aggressive Road Safety Industry, criminally to my mind, to confuse reckless driving with 'speeding' in order to justify a profitable policy of unnecessarily hampering and criminalising perfectly safe drivers and to ignore real accident causes whilst doing it. I refer to this effect as 'Speed Kills! kills'.

But what is the issue anyway? After 300 billion driver miles a year there is less death on the road, from all causes, than from accidents in the home. I think the answer can be found in the countless billions of pounds being consumed yearly by an insatiable Road Safety Industry; I can think of no other explanation for all this nonsense.

It says that the statistics show that the Association of British Drivers has it wrong about too much focus on speed.

Ian's instructor is not at all altruistic in her message and in any case, being a mother of an accident victim, is no qualification either. The

Parliamentary Advisory Committee on Transport Safety, quoted, is only an important sounding private lobby group with vested interests and without any experts in it.

Of course speed is a factor in all road accidents; without speed nothing would be moving on the road at all. So when Julie Townsend of BRAKE says 'It's a contributor to a majority of crashes', I would like her to describe any accident, whether involving planes, trains, bikes or even running, where it is not a 'contributor'. So much for the experts of BRAKE then; perhaps they should just stick to victim support.

But the figures quoted by Wolmar are totally bogus too. For a start, physics would not support the notion that to exceed an arbitrary and unscientific number on a pole, 'speeding' will cause an accident any more than not to won't. Too fast causes them, is often below speed limits and thus most accidents are below the speed limits. Unfortunately most reporting officers are not specialists and do not know this. So all the 28% shows is that 28% of reporting officers ticked a box that should not be there anyway. The correct figure is zero per cent because speeding causes nothing. The millions of speeding tickets issued should each have been after a crash if it were not so.

Christian Wolmar also uses a term favoured by the officials, BRAKE and PACTS. 'Excessive speed'. Where is this in traffic law? It does not exist. It is an element of reckless driving and is nothing to do with 'speeding'. One causes accidents and the other is just coincidental to them. Why use a term, not even recognised in traffic law? It is used Road Safety Industry to confuse reckless driving with 'speeding' in order to justify speed camera policy at the expense of true road safety. I refer to this effect as 'Speed Kills! kills'.

But what is the issue anyway? After 300 billion driver miles a year there is less death on the road, from all causes, than from accidents in the home.

Funny how most of the middle class middle aged think they're the upstanding, law-abiding part of society. They're the ones who habitually break the speed limit, sometimes killing and maiming in the process.

For all those saying that there is no evidence as to the effectiveness of speed cameras, could I suggest that they look here

http://www.bmj.com/content/330/7487/331.full

The study has made use of 21 studies in reaching its conclusions. It may be possible to dispute the conclusions or methodologies used in these studies - but to say that there is no evidence just demonstrates ignorance and too much time listening to garbage such as Top Gear.

I read a couple of years where this statistic came from. It was a study done in the 1970s in the USA. The study put estimated speeds in bands - something like 10mph. Further the statistic seems to have been inflated - it was previously a 20% chance of survival at 40mph (remember the horror adverts of mangled children?)

It would be worth challanging the figures. Even if the 1970s statistics were correct, modern cars are designed to be less deadly than in the days of chrome bumpers and vertical radiator grills. Breaking distances have improved as well.

First of all sincere apologies for repeated post. The system was telling me they were too long and rejecting them; they got shorter and shorter till I gave up.

Re camera stats.I have read enough of them to tell you that they rely on two tricks. One is to mingle death, which is indisputable, and seriously injured which is subjective opinion and in contradiction with A&E figures. Why do the officials insist on mixing fact with fiction? The other is the 'at our sites' regression to the mean trick where a balloon on a stick will give the same survey result.

The fact is that DfT figures clearly show a massive drop in accidents from 1976 until about 95 and the advent of camera partnerships when the drop levelled off. But from the 90s we have had better cars, better braking, airbags, booster seats, better A&E, paramedics and rescue as well as better roads. So the true evidence is that, other than criminalising 100s of thousands of safe drivers, these partnerships and their cameras are a failure.

So before accepting the stats look for 'K/SI'or killed and seriously injured and 'at our sites'. When you see either of those, ignore the claim.

Do any of the people from BRAKE, PACTS, the AA, RAC or even commenting here, bother to survey the speed limit orders when they appear as we all are supposed to?. No? Then how do we know who sets them? What is their expertise in driving? On a recent BBC radio prog I challenged a camera partnership walla as to what he knows about the limits? His response was 'We do not set them and it is not our remit to know about them or survey them'. I came back with 'so here you are aiming cameras at people, prosecuting them and you don't even know how the limits are set! Astonishing. Roll up roll up and follow the money folks.

For all those saying that there is no evidence as to the effectiveness of speed cameras, could I suggest that they look here

http://www.bmj.com/content/330/7487/331.full

The study has made use of 21 studies in reaching its conclusions. It may be possible to dispute the conclusions or methodologies used in these studies

You're certainly right there...

One of the citeria for the installation of a camera was that an atypical number of KSI (Killed / Seriously Injured) accidents should have occurred at the proposed site (actually within IIRC a 1Km rdius of the proposed site - which is why you find cameras in places where there's never been a KSI but the site offers more "opportunities" for revenue collection). Once sited, there is usually a drop in accidents at the site - this is almost always a statistical artifact called the Regreesion To The Mean benefit Illusion (RTTM), ie things go back to "normal" of their own accord... As Keith Peat says, a balloon on a stick would have the same effect.

The report you quote makes mention of RTTM but fails completely to make any allowance for it. It also notes that there were no randomised control groups used - consequently any conclusion that it reaches re the efficacy of speed cameras is essentially invalid.

- but to say that there is no evidence just demonstrates ignorance and too much time listening to garbage such as Top Gear.

Here's a bit of "evidence", taken from my local rag...

Site problems knock out speedtrap plan (Shropshire Star, 30-Sep-2005)

A new speed camera will not be installed on a road which has been branded Shropshire's most dangerous after safety chiefs revealed they were scrapping the plan because of problems with finding a site.

Bosses from West Mercia Safety Camera Partnership have admitted defeat on Smithfield Road in Shrewsbury, because road engineers have been unable to find a suitable location after nearly two years of trying.

But despite the news, the camera partnership today said the number of accidents on the 30mph road had dramatically fallen over the last three years.

At a meeting in March last year camera boss Trevor McAvoy said Smithfield Road had the worst collision record in Shropshire.

He said it eclipsed the A5 and A49 with 65 accidents, seven of them serious, during 1999 to 2001.

But over the last three years there have been just 16 crashes causing injuries, with one serious collision, partnership spokeswoman Vicki Bristow said today.

To summarise the above wondrous example of "shooting yourself in the foot"...

(1) There were 65 accidents in the initial 3-year period.

(2) No camera was actually installed.

(3) The ensuing 3-year period had 16 accidents - a reduction of 76% - which in fact made this "virtual camera" the most "effective" in the entire county.

RTTM. QED.

I'll try and dig out the official "Fourth(?) Year Report" from the DfT, which was the first one to take any notice of RTTM - even if it was hidden in an obscure appendix - that in essense concluded that correcting for trend and RTTM there was no statistical significance in the claimed accident reduction figures at camera sites.

Pogo. Well said and good research. I had already warned the readers of the K/SI and the 'at our sites' regression to the mean stunt without even looking at the report and predicting that is how it would be compiled.

Now two of us, unknown to each other and without collusion, bring this to the attention of Iain but I doubt he is reading it.

People confuse cause with consequence. Iain's instructor's daughter wasn't hit, probably, because the driver was going too fast. But his speed made the difference between her being seriously injured and slightly hurt.

Her daughter might have been standing in the middle of the road with her eyes closed, but actually it's irrelevant, because it's the consequences that matter - ie her injuries that the driver could have guaranteed to have prevented by driving more slowly, when he can't guarantee never to hit someone.

Richard Manns, you're asking the wrong question. Reducing your speed saves lives and there's plenty of evidence for this. If speed cameras save lives it will be because they encourage drivers to reduce their speed.

FF. By focussing on the damage or injury after impact, as you are doing, is not to focus on the cause of the accident FF. Under your logic anyone can do anything silly in the road providing they cannot get hurt?

Why not slow trains for the same logic too? 'Speed kills!' Isn't applied to trains and planes is it?

Why is it that all the costly and very profitable gadgets are promoted but don't actually stop one single accident? Seat belts, booster seats, crash hats, airbags nor cameras? Lets spend the same money stopping the accidents. 'Speeding' cannot and does not cause accidents and cameras van only monitor that but cannot see one single accident cause.

On your logic, let's stop all traffic and get no death and injury on the roads, but 100s of thousands from the economic crash. Every 1 MPH we slow road transport costs about £3billion per annum. How many people could NHS save with that (About 30billion a year)?There is a downside to this multi billion pound industry that is never put in the balance sheet FF.

My comments were aimed at those who said there was no evidence in respect of the effectiveness of speed cameras – who I’m afraid were just plain wrong. As you noted I never said that the evidence was conclusive or otherwise. And in fact if you look at the study it is intellectually honest regarding the weaknesses in the methodologies used in the underlying studies. Just as an aside the BMJ study does not mix up figures for killed and seriously injured as Keith and yourself infer – it has quite clearly disaggregated the results.

Whatever you may say the study does show pretty strong evidence for the reduction in deaths and injuries after the introduction of speed cameras – what it doesn’t demonstrate is causality. This may be because of RTTM or it may be due to some other cause. Where you are very wrong, however, is in making the leap from saying that this “may” be because of RTTM to saying that it “is” because of RTTM and then dismissing the entire case for speed cameras. The right scientific response where such a relationship is found is to gather further evidence, not to leap to the alternative conclusion that there is no relationship and to deny the possibility of causality. The BMJ study makes it pretty clear that the results in respect of speed cameras should be tested against for those at randomly selected controlled sites. Given the availability of data I suspect that this could be done pretty quickly and rapidly, but the Department of Transport currently seems to be guided by prejudice rather than any observance of scientific method. It should be noted that similar arguments were used in the past to rubbish the initial studies demonstrating the links between cancer and exposure to tobacco and asbestos.

The latest research has shown that the probability of death is now seven per cent at 30mph and 31 per cent at 40mph; somewhat removed from the figures used by the propagandists (Iain having been told 90% death rate at 40mph). The figures used in the government campaigns were compiled in the 1970s and hence woefully out-of-date thanks to improvements in car safety and emergency medical care.

These figures used in the child TV and Radio campaigns 'hit me at 40MPH and there is an 80% chance I will live', using a child for emotion, I challenged with the ASA and OFTEL at the time as they were stated as a fact. The basis of my complaint was that they were a fiction and not based on any real accident data at all. You would need hundreds of real impacts at exactly 40 MPH to arrive at that figure. This is not possible to achieve for obvious reasons. Both rejected my complaints, as did the DfT at the time. So now its 31% chance of being killed but that too is theory and equally spurious. I will resubmit my original complaints with this new admission.

Fact is there is more death from accident in the home so the problem on the roads is? Follow the money!

I am afraid you are wrong. DfT stats from 1976 to 2008 show massive drops in accident rates from 76 which levelled out at about 1995 the advent of camera partnerships.

The cameras, like your speedo with a camera cannot see any accident causes and so prosecute for the wrong cause entirely. The figures are always 'at our sites' and thus subject to a regression to the mean.

The partnership claims, now being made from 2007, are entirely consistent with the recession, a massive hike in fuel costs, where the most accident prone group 17-24 year olds cannot afford a gallon of petrol, the 2008 introduction of the national bus pass for another dodgy group, and less business miles being driven.

Keith, I explain in my comment why the injury itself is more important than the cause. If you take the "speed kills" to its logical conclusion then, as you say, we would ban cars entirely. It's not an entirely absurd conclusion because we do in fact ban many other things that are far less dangerous than private cars.

However, we don't ban cars because society tolerates a certain amount of death and injury for the convenience and freedom of private transport. Nobody talks about it in these terms, but that's how it is. So it does come down to faster speeds and more death or lower speeds and less death. One reason why it's important that we have speed limits and they are enforced is that society's compromise between freedom and collateral death and injury is respected.

troymolloy, I think you're right about the figures but the principle still applies: we always want to cust the death and injury rate if we can.

Yes FF but you persist as if the private car is some kind of luxury that can be stopped. Partly because of the Public Transport propaganda. Fact is even in London where there are several buses in every street and trains every 2 minutes in the rush hour, 10 minutes outside those times, it cannot work without the private car. The rest of the country cannot afford TfL and particularly rural areas. So ok, unless we sleep on railway platforms, how does a train get us to and from where we want to be? They mask this by calling cabs 'public transport' to make the rest viable but cabs are purely chauffeur driven private cars. Our economy would collapse and many more die if it were not for the driver and his vehicles. Not the enemy of the State but actually keeping it going.

Keith, you misrepresent my argument. There's no question of stopping private cars. The question is whether the way they are driven should be regulated. I think our society does demand this kind of regulation, as it does for any kind of activity where you run the risk of killing and maiming not just yourself but others around you.

In terms of staistical methodology you are just plain wrong - putting two factors together in the manner you do and then inferring causality just doesn't work, a lot more work is required.

RTTM to the mean can be in either direction and as far as I am aware there is no statistical study which actually tries to identify in which direction it actually is in the case of speed cameras. But the fact that there is some regression in either direction does not tell us anything about the extent of such regression or whether it is sufficient to invalidate the case for speed cameras. As I have said this is an argument for an improved staistical study and not one to jettison the whole thesis that speed cameras reduce traffic accidents.

As for your statement that speeding doesn't cause accidents - well it certainly makes them more likely, don't you remember that stopping distance chart or do you wish to deny physics.

Speeding cannot cause anything, driving too fast does. The problem is that when you set the limits too low, take the science out of it, as in the 2006-2011 review, you create speeders. That is not out of sheer disobedience as most drivers try not to speed. The lower the limit the harder to maintain with constant referral to the speedo. We all know that on a motorway one need not look at the speedo anywhere near as much to maintain 70. By the way motorways and duels are, although fast, by far the safest which rather proves the point.

Outside my house there was a 40 limit with no crashes. They lowered it to 30 on demand of unqualified parochialism. There are still no crashes but now we have speeders. I have had a balloon hanging on my gate since then and there has been no crash in that stretch of road for the 2years it's been there. In fact its gone flat now and still stopping crashes. The millions of speeding tickets handed, without crashes out also shows that a) Speeding does not cause crashes and b)Is evidence of limits too low.

You are not counting the deaths from the poor economics of slowing and hampering a major infrastructure, stopping a motorway for hours, the knock on accidents from the added stress and tiredness and so on. Slowing traffic is not all win win so lets have the negatives of the balance sheet. We certainly will not get it from the Industry that is for sure. AA, RAC? Both in insurance with a vested interest in points and traffic creeping along. PACTS? A private lobby group of vested interest members including public transport and camera manufacturers?

I believe we have to accept attrition for what is a very dangerous activity; it is already lower than in the home and PACTS wants if down by another 1/2. Follow the money

Speeding cannot cause anything, driving too fast does. The problem is that when you set the limits too low, take the science out of it, as in the 2006-2011 review, you create speeders. That is not out of sheer disobedience as most drivers try not to speed. The lower the limit the harder to maintain with constant referral to the speedo. We all know that on a motorway one need not look at the speedo anywhere near as much to maintain 70. By the way motorways and duels are, although fast, by far the safest which rather proves the point.

Outside my house there was a 40 limit with no crashes. They lowered it to 30 on demand of unqualified parochialism. There are still no crashes but now we have speeders. I have had a balloon hanging on my gate since then and there has been no crash in that stretch of road for the 2years it's been there. In fact its gone flat now and still stopping crashes. The millions of speeding tickets handed, without crashes out also shows that a) Speeding does not cause crashes and b)Is evidence of limits too low.

You are not counting the deaths from the poor economics of slowing and hampering a major infrastructure, stopping a motorway for hours, the knock on accidents from the added stress and tiredness and so on. Slowing traffic is not all win win so lets have the negatives of the balance sheet. We certainly will not get it from the Industry that is for sure. AA, RAC? Both in insurance with a vested interest in points and traffic creeping along. PACTS? A private lobby group of vested interest members including public transport and camera manufacturers?

I believe we have to accept attrition for what is a very dangerous activity; it is already lower than in the home and PACTS wants if down by another 1/2. Follow the money